Illumination sources for multicore fiber endoscopes

ABSTRACT

Endoscopes, multicore endoscope fibers and configuration and operation methods are provided. The fibers may have hundreds or thousands of cores and possibly incorporate working channel(s) and additional fibers. The fiber may be used at different optical configurations to capture images of tissue and objects at the distal tip and to enhance a wide range of optical characteristics of the images such as resolution, field of view, depth of field, wavelength ranges etc. Near-field imaging as well as far-field imaging may be implemented in the endoscopes and the respective optical features may be utilized to optimize imaging. Optical elements may be used at the distal fiber tip, or the distal fiber tip may be lens-less. Diagnostics and optical treatment feedback loops may be implemented and illumination may be adapted to yield full color images, depth estimation, enhanced field of views and/or depths of field, and additional diagnostic data.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. patent applicationSer. No. 14/805,915 filed on Jul. 22, 2015, which claims priority under35 U.S.C. §119 to U.S. Provisional Patent Application No. 62/028,346filed on Jul. 24, 2014 and to U.S. Provisional Patent Application No.62/119,832 filed on Feb. 24, 2015, all of which are incorporated hereinby reference in their entireties.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to the field of endoscopy, and moreparticularly, to multicore fiber endoscopes.

2. Discussion of Related Art

Endoscopes in various configurations allow efficient treatment of arange of medical problems, as well as means for manipulating differentsituations with limited access. Endoscope operations are challenging inthat illumination, detection and treatment are confined to long andnarrow operations modes. Fiber optics technology is a central enablerfor such techniques, and fiber-based endoscope experience continuousimprovements.

SUMMARY OF THE INVENTION

The following is a simplified summary providing an initial understandingof the invention. The summary does not necessarily identify key elementsnor limit the scope of the invention, but merely serves as anintroduction to the following description.

One aspect of the present invention provides an endoscope having adistal tip and a proximal tip, the endoscope comprising at least onemulticore fiber module comprising at least one hundred cores distributedat a fill factor smaller than ¼, an illumination source coupled to theat least one multicore fiber module and configured to deliverillumination thereto, at least one optical element, in opticalcommunication with the cores, at the distal tip, a detector, in opticalcommunication with the cores, at the proximal tip, and a processorconfigured to receive images from the detector; wherein the endoscope isconfigured to implement super-resolved imaging by micro scanning over apitch distance between the cores, and wherein the endoscope isconfigured to implement three dimensional sensing by handling the coresgroup-wise with respect to radiation delivered therethrough, and to atleast one of: enhance, by configuring the at least one optical element,a field of view of the endoscope beyond a region facing the cores at thedistal tip, and enhance, by configuring the at least one opticalelement, a depth of field of the endoscope beyond a region congruent tothe distal tip.

These, additional, and/or other aspects and/or advantages of the presentinvention are set forth in the detailed description which follows;possibly inferable from the detailed description; and/or learnable bypractice of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of embodiments of the invention and to showhow the same may be carried into effect, reference will now be made,purely by way of example, to the accompanying drawings in which likenumerals designate corresponding elements or sections throughout.

In the accompanying drawings:

FIGS. 1A-1E are high level schematic illustrations of endoscopeconfigurations according to some embodiments of the invention.

FIGS. 2A-2C are high level schematic illustrations of fiber crosssections having a large number of cores in their electromagneticpropagation region(s), according to some embodiments of the invention.

FIGS. 2D and 2E are high level schematic illustrations of fiberproduction by packing fiber modules, according to some embodiments ofthe invention.

FIGS. 3A-3C are high level schematic cross section illustrations offibers having working channels and additional channel positions fortreatment or illumination fibers, according to some embodiments of theinvention.

FIG. 3D is a high level schematic illustration of a fiber with anassembled front lens, according to some embodiments of the invention.

FIGS. 3E-3G are high level schematic illustrations of a defoggingmechanism and its effects, according to some embodiments of theinvention.

FIGS. 4A-4D are high level schematic illustrations of hollow endoscopefibers having optical elements at the distal tip which compensate forthe central void, according to some embodiments of the invention.

FIGS. 5A-5C are high level schematic illustrations of optical elements,according to some embodiments of the invention.

FIGS. 6A and 6B are high level schematic illustration of fiber crosssections with different configurations of the cores, according to someembodiments of the invention.

FIG. 6C illustrates comparative experimental results of full core andhollow core fibers, according to some embodiments of the invention.

FIG. 7 is a high level schematic flowchart illustrating a method,according to some embodiments of the invention.

FIGS. 8A-8E are high level schematic illustrations of experimentalimaging results for bundled fibers, according to some embodiments of theinvention.

FIGS. 9A-9D are images that provide examples for performance of theendoscope, according to some embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Prior to the detailed description being set forth, it may be helpful toset forth definitions of certain terms that will be used hereinafter.

The terms “distal” and “proximal” as used in this application refer tothe ends of the endoscope. The end and associated parts of the endoscopewhich are far from the endoscope's interface (detector or eye) and closeto the imaged tissue and to its surroundings is termed the distal end,while the end and associated parts of the endoscope which are close tothe endoscope's interface and are remote from the imaged tissue, beingtypically outside the body is termed the proximal end. The term“reflected” as used in this application refers to a change in adirection of an illumination wavefront which impacts one or more imagedobject or tissue. The term “reflection” is understood broadly as anyradiation gathered by the fiber, irrespective of the source of theillumination which is reflected by the object(s) and/or tissue(s).

The term “near field imaging” as used in this application refers to theformation of an image (of imaged objects, tissues and/or theirsurroundings) at the distal end of the endoscope fiber, typically at thefiber's tip. The imaged is then typically transferred through the fiberto the detector, possibly through proximal optical elements. The term“near field imaging” may relate to different types of optical systems,including direct imaging without any optical elements between the imagedobject or tissue and the fiber tip as well as to imaging through opticalelement(s) such as lenses.

The term “far field imaging” as used in this application refers to theformation of a Fourier transform of imaged objects, tissues and/or theirsurroundings at the distal end of the endoscope fiber (e.g., the distalend of the endoscope fiber is at the aperture or pupil plane of theoptical system), typically at the fiber's tip. The image of the imagedobjects, tissues and/or their surroundings may be formed at the proximalend of the endoscope fiber, typically at the fiber's proximal tip ordirectly on the detector, possibly through proximal optical elements.The term “far field imaging” may relate to different types of opticalsystems. In one example, “far field imaging” may be direct in the sensethat no optical elements are used between the imaged object or tissueand the distal fiber tip, which delivers radiation entering the fiberalong the fiber to the detector at the proximal end of the fiber. Inanother example, “far field imaging” may be carried out with opticalelements positioned between the imaged object or tissue and the distalfiber tip, with the distal fiber tip being at least approximately at theFourier plane (also termed aperture plane and pupil plane in differentcontexts) of the optical elements.

With specific reference now to the drawings in detail, it is stressedthat the particulars shown are by way of example and for purposes ofillustrative discussion of the preferred embodiments of the presentinvention only, and are presented in the cause of providing what isbelieved to be the most useful and readily understood description of theprinciples and conceptual aspects of the invention. In this regard, noattempt is made to show structural details of the invention in moredetail than is necessary for a fundamental understanding of theinvention, the description taken with the drawings making apparent tothose skilled in the art how the several forms of the invention may beembodied in practice.

Before at least one embodiment of the invention is explained in detail,it is to be understood that the invention is not limited in itsapplication to the details of construction and the arrangement of thecomponents set forth in the following description or illustrated in thedrawings. The invention is applicable to other embodiments or of beingpracticed or carried out in various ways. Also, it is to be understoodthat the phraseology and terminology employed herein is for the purposeof description and should not be regarded as limiting.

Endoscopes, multicore endoscope fibers and configuration and operationmethods are provided. The fibers may have hundreds or thousands of coresand possibly incorporate working channel(s) and additional fibers. Thefiber may be used at different optical configurations to capture imagesof tissue and objects at the distal tip and to enhance a wide range ofoptical characteristics of the images such as resolution, field of view,depth of field, wavelength ranges etc. Near-field imaging as well asfar-field imaging may be implemented in the endoscopes and therespective optical features may be utilized to optimize imaging. Opticalelements may be used at the distal fiber tip, or the distal fiber tipmay be lens-less. Diagnostics and optical treatment feedback loops maybe implemented and illumination may be adapted to yield full colorimages, depth estimation, enhanced field of view and/or depth of fieldand additional diagnostic data, as disclosed below.

In the following, various embodiments of multicore endoscope fibers aredisclosed. The described embodiments are roughly and not exclusivelydescribed in groups relating to the following traits. Certain endoscopeembodiments may implement far field imaging (see FIG. 1A below), e.g.,have the image formed at the proximal end of the endoscope fiber, whilecertain endoscope embodiments may implement near field imaging (see FIG.1B below), e.g., have the image formed at the distal end of theendoscope fiber. Both far field and near field implementations, may havedistal optical elements between the imaged objects or tissues and thedistal fiber tip (see FIG. 1C below), or may operate without such distaloptical elements (see FIG. 1D below). Each of the four combinations (farfield with or without distal optical elements and near field with orwithout distal optical elements) has different features, advantages anddisadvantages as exemplified in Table 1, and may be selected accordingto specific implementation scenarios. Alternation of the combination maybe carried out between applications or in real time, to combineadvantages of different configuration types. It is further noted thatendoscopes may be designed to have several combinations, e.g., a part ofthe fiber face (or certain fiber modules) having distal optics forimaging far objects and another part of the fiber face (or other fibermodules) lacking distal optics for microscopic imaging.

TABLE 1 Characteristics of different embodiments Far-field imagingNear-field imaging Distal fiber tip Fourier plane Image plane Withdistal optics Larger region of interest Larger field of view, Imagemultiplexing, larger energetic efficiency Larger field of view which mayinclude working channel without compromising (central) regions in thefield of view No distal optics Wavefront sensing, Auto focus and opticaloptical zooming zooming capabilities Simpler production and fibermanagement

Certain embodiments comprise lens-less embodiments in which the distalfiber tip lacks optical elements. Lens-less embodiments may implementeither far-field or near-field imaging, and may utilize structuralfeatures to enhance optical resolution, apply super-resolution methodsand retrieve wavefront information while reducing crosstalk between thecores.

Endoscope embodiments may have full tip cross sections or have workingchannel(s) within the imaging fiber characterized by differentconfigurations and uses, integrating additional fibers etc., in whichcase the cores and optical elements may be configured to overcome thereduction of the field of view due to the incorporation of the workingchannel.

In the following, various configurations of the large number of cores inthe fiber are disclosed, which provide solutions to various issues suchas reducing crosstalk between the fibers, overcoming material losses,achieving enhanced resolution by different methods, providing requiredmechanical characteristics and optimizing the imaging performances ofthe endoscope fibers. The disclosed endoscopes may serve differentpurposes, e.g., may be designed as a laparoscope or an ureteroscope. Itis noted that elements disclosed in the context of some of theembodiments are not necessarily limited to these embodiments but may beimplemented within other embodiments as well.

FIGS. 1A-1E are high level schematic illustrations of endoscopeconfigurations according to some embodiments of the invention. Proposedmicro endoscope 105 is constructed from large plurality of cores (e.g.one hundred cores or more, hundreds of cores, thousands of cores, incertain embodiments tens or hundreds of thousand cores per fiber orfiber module, reaching over a million cores in certain fiberendoscopes), each responsible for transferring a single or a largenumber of spatial degrees of freedom out of which at the output,proximal end (the one external to the patient body), a high resolutioncolor image may be constructed. Multi-core fiber 100 exhibits a highdegree of flexibility in its optical design, as exemplified below, whichmay be utilized and adapted for specific applications, for example forureteroscopes with a large working channel and a small external diameteror for laparoscopes with a very high resolution obtained at a smallexternal diameter.

Endoscope 105 may be configured to carry out far-field imaging,near-field imaging or a combination of far-field imaging and near-fieldimaging. Irrespectively of the imaging mode, endo scope 105 may beconfigured to have one or more optical elements 140 at a distal tip 101of fiber 100 or have no optical elements between tip 101 and imagedtissue(s) or object(s) 70. Certain embodiments may comprise removable orreconfigurable optical elements 140 at tip 101 and/or optical elements140 affecting only parts of the surface of distal tip 101 (e.g.,sub-group(s) of the cores).

Certain embodiments comprise endo scopes 105 having a plurality offibers 100, grouped together, each having at least one hundred coresdistributed at a fill factor smaller than ¼, or even smaller than 1/9,at least one photonic illumination fiber, and at least one opticalelement at a distal tip of fibers 100, which may be configured toenhance a field of view and/or a depth of field of endoscope 105 beyonda region facing a tip of fibers 100 and congruent thereto (see detailsbelow). Endoscope 105 may be further configured to implement threedimensional sensing by handling the cores group-wise with respect toradiation delivered therethrough (see details below). Endoscope 105 maybe further configured to super-resolved imaging by micro scanning over apitch distance between the cores (see details below). Endoscope 105 maybe configured to comprise a LED (light emitting diode) light sourcelocated at distal tip 101 as the illumination source.

FIG. 1A schematically illustrates far-field imaging, in which an image73 (indicating any kind of electromagnetic signal reflected from tissueor object 70) is delivered through tip 101 and fiber 100 to yield image75 on detector 91. Tip 101 may be a Fourier plane (also termed apertureplane or pupil plane) at which the Fourier transform 74 of image 73enters fiber 100. It is noted that the Fourier plane may be locatedanywhere along fiber 100 as well as distally or proximally to fiber 100,in different embodiments of the invention, and be optically transformedto image 75 on detector 91. Alternatively or complementary, Fourierimage 74 or derivatives thereof may be measured at detector 91, and/ormanipulated to enhance imaging parameters such as resolution, field ofview and depth of focus, as non-limiting examples. Optical elements maybe introduced distally or proximally to fiber 100 to modify ormanipulate the radiation entering tip 101 and the radiation falling ondetector 91, respectively.

FIG. 1B schematically illustrates near-field imaging, in which image 73yields image 75 at fiber tip 101. Image 75 is then delivered, possiblythrough optical elements, to detector 91 through fiber 100. It is notedthat image 75 may be formed within fiber 100 and not necessarily exactlyat tip 101. Image 75 delivered via fiber 100 may be measured at detector91, and/or manipulated to enhance imaging parameters such as resolution,field of view and depth of focus, as non-limiting examples. Opticalelements may be introduced distally or proximally to fiber 100 to modifyor manipulate the radiation entering tip 101 and the radiation fallingon detector 91, respectively.

FIG. 1C schematically illustrates optical configurations having one ormore optical element(s) 140 at the distal end of fiber 100, at proximityto imaged tissue 70. Optical element(s) 140 may be attached to tip 101or may be somewhat distally removed from tip 101 (e.g., held by spacersat a distance therefrom). Each optical element 140 may be in opticalcommunication with a respective core or a respective group of cores.Proximally, illumination 85 is delivered to fiber 100 by an illuminationsource 160, and reflected illumination (e.g., in far-field, innear-field or in an intermediate plane) is directed from the cores to adetector 91, e.g., via a beam splitter 90. Proximal optical elements maybe set and used to manipulate illumination 85 and the reflectedillumination, as symbolized below (FIG. 1D) by lenses 84, 94respectively. One or more processor(s) 170 may be configured to controlthe illumination and/or process the detected illumination, as well ascontrol illumination and image beams in case there are controllableelements in the optical path.

FIG. 1D schematically illustrates optical configurations having nooptical element(s) (also termed below “lens-less” configurations) at thedistal end of fiber 100, so that fiber tip 101 is used directly todeliver and receive illumination to and from imaged tissue 70.Illumination 85 is delivered to fiber 100 proximally, e.g., via anoptical element 84 such as a lens, and reflected illumination isdirected to detector 91 via another optical element 94, e.g., a lens.One or more processor(s) 170 may be configured to control theillumination and/or process the detected illumination, as well ascontrol illumination and image beams in case there are controllableelements in the optical path. In certain embodiments, lens-lessconfigurations may be configured to generate image at “contact mode”,e.g., with close proximity of the fiber tip to the examined tissue, toyield microscopic resolution determined by the sizes of the cores.

In certain embodiments, proximal optical elements 94 (and possiblyoptical elements 84 too) may be variable and be used to adjust the planeand depth of focus of captured images in far-field imagingconfigurations, especially in lens-less configurations.

FIG. 1E is a high level schematic block diagram illustrating endoscopeconfigurations according to some embodiments of the invention. Variousembodiments are illustrated, which may be stand-alone embodiments or beimplemented in any combination thereof. In particular, variousembodiments of illumination source 160 and of configurations ofprocessor 170 are presented, which may be used to improve the spatialresolution, in particular when using super resolution algorithms,improve the beam quality and/or enhance the functionality of endoscope105 with respect to its medical uses and image quality. Embodimentsillustrated in FIG. 1E may be applied to any embodiment of endoscope 105described herein. It is noted that illumination source 160 may beconfigured to deliver illumination 85 through one or more dedicatedillumination fiber(s) 102 and/or through multicore fiber 100. Forexample, illumination fiber(s) 102 may be multimode fiber(s), possiblymade of glass fiber, which are associated with multicore fiber 100,e.g., attached thereto or positioned in a cavity in multicore fiber 100.Alternatively or complementarily, illumination fiber(s) 102 may bepositioned to illuminate tissue 70 in any other spatial relation tomulticore fiber 100, possibly in no mechanical association therewith. Incertain embodiments, one or more of illumination fiber(s) 102 may besingle mode fibers. It is noted that the spatial relation betweenillumination fiber(s) 102 and multicore fiber 100 may be configured tohave multicore fiber 100 receive radiation (illuminated by illuminationfiber(s) 102) which is reflected off tissue 70 and/or transmittedthrough tissue 70, depending on specific use conditions.

In some embodiments, illumination source 160 may comprise a coherencemodulator 162 configured to enable processor 170 to implement algorithmsfor improving super resolution results 172. For example, coherencemodulator 162 may be configured to use a coherence modulation ofillumination 85 that reduces speckle patterns by modulating thecoherence using Barker codes rather than random prior art modulation.Advantageously, using Barker codes may reduce the required number ofmodulation steps for a given reduction of speckle patterns due to theorthogonality between the Barker codes and other characteristics oftheir definition. Specific Barker codes may be selected to optimizetheir application.

In some embodiments, illumination source 160 may comprise multiplenarrowband wavelengths 62 (e.g., narrowband spectral ranges aroundspecified wavelengths) which may be used in processors 170 configured toprovide diagnostics using one or more wavelength combinations 174,discussed below in more detail, and/or configured to implementwavelength multiplexing super resolution 176 by changing the ratiosbetween specific wavelengths (e.g., between narrowband red, green andblue sources 62)—to achieve improved super resolution results 180.

In some embodiments, illumination source 160 may comprise one or morephotonic crystal fiber (PCF) 164 configured to deliver wideband whitespectrum 177 into dedicated illumination fiber(s) 120 and/or multicorefiber 100, e.g., utilizing supercontinuum effects (bandwidth broadeningdue to nonlinear effects) to provide white illumination of tissues thatis closer to natural wideband illumination than illumination withnarrowband red, green and blue sources 62 which are delivered to PCF164. PCF 164 may be coupled to one or more narrowband sources 62 anddesigned to have zero dispersion point(s) at the wavelengths ofsource(s) 62 to yield spectral broadening. Using several multiplenarrowband wavelengths 62 may provide wideband white spectrum 177through a combination and merging of the broadened spectra of source(s)62. Improved white spectrum 177 may be advantageous to provide truerimaging colors be endoscope 105.

In some embodiments, illumination source 160 may comprise structuredlight patterned illumination 168, which may be used in processor 170configured to provide 3D sensing 178 by analyzing the illuminatedpatterns on the tissue and/or improved super resolution results 180 byutilizing the parameters of the temporally changing spatially projectedpatterns of illumination 168 to implement temporal multiplexing superresolution 179.

In some embodiments, illumination source 160 may comprise one or morelaser source(s) 64 (possibly narrowband sources 62) in illuminationsource 160 and at least one beam shaping element 182 at the distal endof multicore fiber 100 which is configured to generate an optimized beamprofile 184 to improve illumination 85. For example, beam profile 184may comprise a uniform illumination distribution in space or arectangular uniform profile (top hat illumination distribution), whichare advantageous with respect to prior art Gaussian illuminationdistribution with respect to various parameters of the resulting images.The coherence of laser source(s) 64 may be used to shape illuminationbeam 85 efficiently by beam shaping element 182. In some embodiments, atleast one beam shaping element 182 may be set at the proximal end ofmulticore fiber 100.

In some embodiments, illumination source 160 may comprise one or morelaser treatment source(s) 66 which are configured to apply a specifiedtreatment 67 by endoscope 105, e.g., to a tissue. For example treatment67 may be applied to kidney stones in endoscope 105 designed as anureteroscope, as described below in more details.

FIGS. 2A-2C are high level schematic illustrations of fiber crosssections having a large number of cores 115 in their electromagneticpropagation region(s) 110, according to some embodiments of theinvention. Fiber(s) 100 may comprise central or eccentric optical cores(110) and/or may have hollow, central or eccentric region(s) (112) thatmay be used for treatment such as energy delivery, suction,illumination, drug delivery etc. Illumination means (such as dedicatedillumination fiber(s) 102), may be integrated in various ways within themulticore fibers 100. Selection of near-field or far-fieldconfigurations, as well as selection if and which optical elements 140are inserted distally to the tip, may be carried out under considerationof the tradeoffs between the different applications (see e.g., Table 1and other examples below). For example, considerations concerningproduction, use, optical characteristics and algorithmic parameters maybe balanced differently at different embodiments to optimize endoscope105 to a wide range of performance and device requirements.

Fiber 100 illustrated in FIG. 2A may have any form of cross section,e.g., square as illustrated in a non-limiting manner, round, hexagonal,elliptic etc. While FIG. 2A illustrates a solid cross section of fiber100, FIG. 2B illustrates hollow endoscope having a void 112 within fiber100 that may be used for different purposes as disclosed below (e.g., asa working channel for inserting a tool or carrying out suction, forincorporating additional fibers etc.). Fibers 100 may be square, roundor have any other form, and void 112 may too have any shape and anyposition within fiber 100, void(s) 112 and fiber 100 may have anydimensions (R_(i), R_(o), D, W etc.), and voids may also be multiple(e.g., fiber 100 may enclose two or more voids), all designed accordingto requirements from the endoscope. FIG. 2C schematically illustratesmulticore fiber 100 with cores 115 grouped into “super core” groups 116that may be configured to sense wavefronts in lens-less configurations,as explained below.

Multicore fiber 100 may be made of biocompatible materials in case ofmedical uses, e.g., polymers such as PMMA (poly-methyl methacrylate) andPS (polystyrene) and may be flexible. Fiber 100 may also be made ofnon-compatible materials and be flexible or rigid in case of industrialuses. Fiber 100 may be configured to have a flexibility characterized bya Young's modulus smaller than 10 GPa and to be disposable. Fiber 100may thus be more flexible than glass fiber (having a Young's modulus ofabout 65 GPa), and may reach PMMA flexibility (Young's modulus between1.8 and 3.1 GPa) or higher flexibility.

Various embodiments compensate for the reduced transparency of polymerfibers with respect to glass fibers, using means such as fibermaterials, configuration of cores and interspaces, number and sizes ofcores, material modifications of different fiber parts, control over thenumber of propagation modes in cores 115, optical means such as lensesor prisms at either side of fiber 100 and their configuration, designand application of different types of illumination and algorithmicsolutions, all of which are exemplified below in a non-limiting manner.The following disclosure also addresses ways to control cross talkbetween cores 115 (e.g., interaction effects between radiationpropagating in adjacent cores 115) and ways to improve the informationcontent and to enhance treatment-relevant information of the detectedimages.

Illumination may comprise coherent light or incoherent light, anyspectral pattern (broad or narrow wavelength ranges, continuous ordiscrete ranged), polarized (in various patterns) or non-polarized lightand different ranges in the visual or infrared ranges. Materialdifferences between cores, interspaces and outer cladding may comprisedifferent materials, using air cores or air interspaces, and doping anyof the fiber regions to influence their refractive indices, as explainedin more details below. It is noted that any of the embodiments presentedbelow may be used in any of the other embodiments described herein, aslong as they are compatible. Particularly, computational methods opticalmethods and fiber design considerations described in the context of anyembodiment may be applied to other embodiments as well.

FIGS. 2D and 2E are high level schematic illustrations of fiberproduction by packing fiber modules, according to some embodiments ofthe invention. Multi-core fibers 100 may be produced using fiber modulesor units 117. Each fiber module 117 is itself a multicore fiber,possibly configured to have uniform dimensions. Such embodiments arereferred to as bundled fibers, and may bundle any number of fibermodules 117 in any configuration (e.g., 2×2 modules, 3×3 modules etc.).Fiber module 117 may have any form, such as square, rectangular, roundor elliptic, and may be packed into fibers 100 having a wide range offorms and configurations, Introducing fiber modules 117 having anintermediate dimension between cores or core groups and whole fiber 100(each module 117 may have e.g. tens, hundreds or thousands of cores)enables simpler production and higher flexibility on forming fiber 100from fiber modules 117. For example, as illustrated in FIG. 2D,rectangular fiber 100 may be assembled from rectangularly arrangedsquare fiber modules 117, e.g., using a package support 118A and arespective attachable cover 118B. Fiber modules 117 may simply bemechanically held by package support 118A and cover 118B at certainregions along fiber 100 and/or fiber modules 117 may be glued togetheror otherwise attached at least at certain regions. In another example,illustrated in FIG. 2E, fiber modules 117A, 117B may be arranged aroundvoid 112. In certain embodiments, fiber modules 117A, 117B may bearranged to differ in their observation angles and/or in opticalelements 140 attached at fiber tip 110 (see e.g., below, FIGS. 4A-4D).For example, fiber units 117A may be configured to cover a field of viewin front of void 112 (e.g., be inclined inwards or have respectiveoptical elements) while fiber units 117B may be configured to cover afield of view laterally beyond tip 101 (e.g., be inclined outwards orhave respective optical elements). For example, non-limiting inclinationangles may be 5-20° inwards and 10-50° outwards. Respective packaging orattachment configurations may be applied to fixate fiber modules 117A,117B in their respective positions and angles. In certain embodiments,the annular arrangement of fiber modules 117A, 117B may be at thefiber's distal end, while fiber modules 117A, 117B may be separated andre-arranged differently at the fiber's proximal end, e.g., into arectangular form to cover a face of a single rectangular detector. Thusflexibility in production and use is achieved, which enables independentoptimization of the spatial distribution of the fiber modules at eitherend of fiber 100, to enhance both the optical sensing at the distal endas well as the detection and processing at the proximal end.

FIGS. 3A-3C are high level schematic cross section illustrations offiber 100 having working channel 112 and channel positions 120 fortreatment or illumination fibers 102, according to some embodiments ofthe invention. Working channel 112, depicted as void 112 within fiber100, is surrounded by electromagnetic propagation multicore fiber region110. Treatment and/or illumination fiber(s) 102 may be integrated intofiber 100 of the endoscope in a way that allows combined imaging andtreatment using one fiber, immediate image feedback of the treatmentetc. Such combination may be used e.g., as ureteroscope or as any othertype of endoscope. In certain embodiments, positioning additional fibersin channels 120 near working channel 112 may be configured to cool downthe fibers (e.g., treatment fibers) by the liquids flowing throughworking channel 112.

In the illustrated examples, treatment or illumination fibers 102 may beinserted at indicated positions 120 (e.g., grooves, or channels), e.g.,at an inner wall of multi-core imaging region 110 in fluid communicationwith working channel 112, e.g., on the periphery of voids 112 (FIG. 3A,channel diameter e.g., ca. 250 μm), at an outer wall of multi-coreimaging region 110 in fluid communication with the surroundings of fiber100, e.g., on the periphery of fiber 100 (FIG. 3B, channel diametere.g., ca. 250 μm), within multi-core imaging region 110 (FIG. 3C,channel diameter e.g., ca. 200 μm), or combinations of thesepossibilities. Integration of the treatment or illumination fibers 102may be carried out before, during or after production of fiber 100. Incertain embodiments, glass treatment or illumination fibers 102 may beinserted into grooves 120 after pulling polymer fiber 100.

In certain embodiments, treatment or illumination fibers may beconfigured and controlled to operate collectively, simultaneously orsequentially, to achieve a desired illumination and/or treatment. Forexample, the treatment channel may be split into several low powerchannels 120 to have thinner channels and lower power delivery througheach channel. Such configuration may enable increasing the mechanicalflexibility of the endoscope, which is very important, e.g., in thefield of ureteroscopy. Furthermore, the usage of hollow channels 120 forinserting the external illumination or treatment fibers provides adevice configuration exhibiting self-alignment.

FIG. 3D is a high level schematic illustration of fiber 100 with anassembled lens 119, according to some embodiments of the invention. Amodular construction of fiber 100 (see e.g., FIGS. 2D, 2E) may be usedto modify some of fiber modules 117 to incorporate features into fiber100 in a simpler manner than incorporating these features into a uniformfiber. fiber modules 117D may be configured in a modular, building blockstyle manner to form various cross sectional organizations with respectto form and functionality of the endoscope. In the illustrated exampleof certain embodiments, two non-adjacent fiber modules 117D may becoated with a conductor (e.g., a metal) while the rest of fiber modules117C may be uncoated (and insulating). Such configurations may be usedto deliver electricity to fiber tip 101. For example, electromagneticsignals or electromagnetic radiation may be delivered via fiber modules117D to adjacent tissues or to associated devices or components (e.g.,checking equipment or endoscope instrumentation). In the illustratedexample, electromagnetic energy may be delivered to distal lens 119 forheating it to prevent fogging upon entry to the body. In certainembodiment, an antenna structure (not shown) may be designed upon lens119, which receives electromagnetic radiation to heat lens 119 withoutusing contacts. In certain embodiments, radiofrequency (RF) treatmentmay be applied to tissue or objects surrounding fiber tip 101 via theconductive coating of fiber modules 117D.

FIGS. 3E-3F are additional high level schematic illustrations of adefogging mechanism 121 and its effects, according to some embodimentsof the invention. FIG. 3E illustrates lens 119 coated by a conductivecoating 122 connected to an electric circuit 123 configured to heat lens119 via coating 122, to prevent fog and to defog lens 119 when required.FIG. 3F exemplifies image deterioration by fog accumulation—the topimage (A) taken a short time after the beginning of fog accumulation,the bottom image (B) taken later, with the object, marked by an arrow,barely visible. FIG. 3G illustrates the image after defogging—bothobject and illumination spot are clear again. It is emphasized that asendoscope 105 may be designed to be very thin (e.g., 0.5 mm in diameter)while providing high resolution images, and distal lens 119 may also beultra-thin. The disclosed defogging mechanism provides effective controlof the temperature of lens 119 using a small amount of electrical power,to prevent fogging and overcome an important prior art limitation.

In certain embodiments, endoscope 105 may be operated in the far field(FIG. 1A) or in the near field (FIG. 1B) by properly adapting the focallength of the external optics (the one outside the patient's body, e.g.,optical elements 84, 94) to the working distance of treated tissue 70from the distal tip of the endoscope. Fiber 100 may be configured todeliver full images even with working channel 112 in the middle of theimaging surface by employing far field imaging, e.g., using imaging lens94 adapted to have a central blocked aperture.

In far field imaging configurations having lens-less fiber tip 101,obtained images may have a number of pixels that is not related to thenumber of cores 115, enhancing the image resolution with respect to nearfield embodiments. For example, certain embodiments comprise using asdetector 91 an integral imaging sensor capable of sensing wavefront orthe 3D topography of inspected tissue 70. In such embodiments, cores 115may be configured to have a small number of possible spatial modes,resembling the Shack-Hartmann interferometer or a wavefront sensor.

In certain embodiments, cores 115 may be grouped into “super-cores” 116(see FIG. 2C), each comprising a group of adjacent cores 115. Each“super-core” 116 may be handled as a single wavefront sensing elementwhich delivers information about the wavefront by comparing radiationpropagating through individual core members 115 within each “super-core”116 (or light field sensing. e.g., comparing light directions atdifferent cores operating in near field and multi-mode). The grouping ofcores 115 into “super-cores” 116 may be uniform across the face of fiber100 or be variable, some core groups being larger than others, see e.g.,the larger central core group in FIG. 2C).

The grouping of cores 115 may be changed in time according to imagingperformance preferences, based e.g., on an even (or uneven) distributionof cores 115 across fiber 110. It is noted that in such configurations atradeoff exists between depth measurements and resolution. A largernumber of cores 115 in each “super-core” 116 provides more details aboutthe three dimensional structure of the imaged region by using moredetailed wavefronts, while smaller numbers of cores 115 per group 116and no grouping at all provide higher resolution. The grouping of cores115 may hence be designed or modified according to spatially andtemporally changing imaging requirements. Complementarily, cores 115 maybe handled by processor 170 group-wise with respect to the radiationdelivered therethrough, to implement each group 116 as a wavefrontsensor. The allocation of cores 115 to core groups 116 may be carriedout dynamically, e.g., by processor 170. Additionally, groupingconsiderations may accompany other considerations regarding imagingperformance such as suggested techniques for enhancing resolution and/ordepth measurements.

In certain embodiments, near field implementations may comprise sensingthe light field between the cores (operating in multi-mode), e.g.,measuring directional components of the radiation to yield 3D imaging.Light field sensing may be carried out groupwise with respect to thecore grouping.

In certain embodiments, endoscope fiber 100 may comprise multiple cores115 that are not positioned at equal distances but interspaced unevenly(see FIG. 2A for a schematic illustration). Uneven (irregular)distribution of cores 115 (e.g., a spatial distribution that does notcoincide with the spatial distribution of pixels on detector 91)enables, when working in the far-field conditions, to obtain superresolved images since the sampling of cores 115 in the aperture plane£Fourier plane) is not uniform and thus the sampling at the apertureplane does not affect the field of view or generate visible limitationsin the image plane. The distribution of cores 115 and the interspacesacross fiber 100 may be designed to optimize resolution enhancementusing algorithmic and optical techniques. Indeed, increasing thedistances between cores 115 may provide larger benefits frommicro-scanning and application of other super resolution techniques.

In certain embodiments, the optical design of fiber tip 101 may beconfigured to have working channel 112 positioned asymmetrically and notcentrally within the cross section of the tip (not concentric to theimaging channel). The shape of working channel 112 may be configured todifferent than circular (e.g., elliptic, elongated, polygonal etc.) inorder to better encode the optical transfer function (OTF). The workingchannel shape may be configured to improve inversing the OTF and thealgorithmic correcting of the image via the image post processing toyield a super resolved image.

In certain near-field imaging embodiments, an increased depth of focusmay be achieved in lens-less embodiments by selecting the best focalpositions that can provide the sharpest contrast per each pixel in thegenerated image, from images captured at different tip positions withrespect to tissue 70. The best focus for each pixel may be selected froma plurality of images captured at different tip positions.

In certain embodiments, optical elements 140 may be attached to orproduced at distal fiber tip 100 (facing tissue 70). Optical elements140 may be used to enhance imaging in both far-field imaging andnear-field imaging. For example, optical elements 140 may be used tocontrol the field of view, increasing it beyond the edges of tip 101outwards and/or inwards (in case of a designed working channel void112).

FIGS. 4A-4D are high level schematic illustrations of hollow endoscopefiber 100 having optical elements 140 at distal tip 101 which compensatefor the central void, according to some embodiments of the invention. Inembodiments with void(s) 112 at the cross section of fiber 100 at tip101, various solutions are presented below for imaging a void-facingarea 72 in addition to (or in place of) region 71 facing cores 115. Itis noted that any type of target 70 may be imaged, e.g., tissue,specific anatomical members, bodily fluids, various stones orobstructions, tumors, foreign bodies etc.

In certain embodiments, illumination source 160 of endoscope 105 and atleast some of the optical elements (e.g., tip optical elements 140,proximal optical elements 84, 94) may configured to image at least apart of the area facing void(s) 112 (e.g., void-facing area 72)differently than a rest of the region facing tip 101 (e.g., core-facingregion 71). The difference in the imaging may lie in any ofpolarization, wavelength, wavelength range and/or timing of theillumination. Non-limiting examples are presented in the following.

Multiple cores 115 may be used to generate a full image, overcoming thelack of cores in hollow region 112 and providing imaging (andillumination) of tissue 70 directly opposite to working channel 112(void-facing area 72). For example, endoscope 105 may be configured toprovide a 90° field of view of fiber 100. FIG. 4A schematicallyillustrates in a non-limiting manner an annular multicore region 110(with an inner radius R_(i) and an outer radius R_(o)) having annularlyarranged optical elements 140. Similar principles may be applied to anygeometric configuration of fiber tip 100, e.g., any form thereof, anyposition and form of void(s) 112, etc.

In certain embodiments, optical elements 140 may comprise gradient index(GRIN) lenses cut at specified angles and glued at tip 101 of microendoscope 105. Each cut GRIN 140 may be cut and positioned to face adifferent direction in order to enhance the fiber's field of view (FOV)to equal the number of GRINs 140 multiplied by the FOV of each GRIN 140(or, complementarily or alternatively, enhance the depth of field byconfiguring some of GRINs 140 to deliver radiation from different depthsof field). The cut of the edge of GRIN lenses 140 may realize a prismcoupling light into that specific GRIN from different predefined sectorsof the field of view. Aspheric lenses may be used as alternative to GRINlenses as optical elements 140.

FIGS. 4B-4D schematically illustrates three possible configurations,according to some embodiments of the invention. The large circleschematically represents the periphery of the total FOV of fiber tip101, which is the boundary of the imaged region facing the cores (71),while the small circles represent the fields of view of individualoptical elements 140, 141, taken in a non-limiting illustrative case tobe equal. For example, tip FOV (region 71 plus void-facing area 72) maybe covered by equally spaced (in FIG. 4B eight) optical elements 140each imaging a peripheral region 145, and an additional optical element141 may be configured to image a central region 146. Void-facing area 72is thus covered centrally by region 146 and its periphery is covered byregions 145. In another example, a larger number (in FIG. 4C twenty one)of optical elements 140 may be configured to have angles covering tipFOV in several concentric circular sets of imaging regions—in theillustrated example twelve peripheral regions 145, eight intermediateregions 146 and one central region. In another example, annularlyarranged optical elements 140 (in FIG. 4D twenty five) may be configuredto have angles covering the tip FOV in a grid-like manner individualregions 145 partly overlapping and covering tip FOV and possibleextending into a larger area. This disclosed method provides highflexibility in adapting fiber tip optical elements 140 to yield arequired field of view.

In certain embodiments, optical element 140 may comprise an annular lenscoupled to an annular prism that directs light from the whole FOV intothe annular lens.

In certain embodiments, possibly without the ring of optical elementsdescribed above, the center of FOV may be imaged using selectiveillumination. Illumination may be directed to the center of FOV and notto its periphery, and accompanying algorithms may be configured toprocess the detected signals to derive images of the FOV center (e.g.,by processor 170).

In certain embodiments, illumination having different polarizations maybe used for the central FOV (e.g., void-facing area 72) and for theperiphery of FOV (e.g., cores-facing region 71), so that the detectedsignal is spatially encoded by the difference in polarization, and maybe decoded to create images of the whole FOV (see more elaborateexplanation below). Optical elements 140 may be birefringent to directlydifferently polarized illumination to different geometric areas.

In certain embodiments, void 112 may be eccentric or divided intoeccentric voids, leaving rooms for ventral cores to image the center ofthe FOV directly.

In certain embodiments, cores 115 may unequally or non-uniformly spacedwithin fiber 100, e.g., such that the positions of cores 115 do notcoincide with the uniform spatial sampling matrix of the pixels ofdetector 91 positioned outside the body. The lack of coinciding betweenthe two grids may be utilized to apply geometric super resolvingalgorithms to improve the quality of the captured image (resembling in asense the micro-scanning technique).

Certain embodiments may implement micro scanning via the spatial coreconfiguration. For example, fiber 100 may exhibit multicore designshaving a low fill factor (the fill factor is the ratio between the corearea and the square of the distance between cores, the latter termedpitch). For example, the core diameter may range between 0.4-2.5 μm andthe pitch may range between 2-10 μm to yield a range of low fill factors(1/(pitch/core diameter)), e.g., fill factors between ¼ and 1/16. Whenthe fill factor is low (e.g., below ¼, below 1/9, e.g., 1/16), simplemovement of tip 101 of the micro endoscope (e.g., movement amplitude mayequal at least the pitch, e.g. a few microns) enable implementation ofthe micro-scanning concept to significantly increase the geometricresolution of the device. (It is noted that in case of imaging withlarge fill factor the micro scanning procedure cannot increase thegeometric resolution of the image but rather only to performover-sampling of the image—because the point spread function (PSF) ofthe sampling pixel/core itself limits as a spatial low pass theobtainable resolution.) In certain embodiments, spatial scanning methodsand temporal scanning methods according to the present disclosure may becombined and adapted to imaging requirements.

In certain embodiments, illumination channel 85 may have time-varyingoptics which realizes a spatial scanning of the illumination spot. Thespatial illumination scanning may be used to construct a wide fieldimage having large field of view which is not affected by the workingchannel positioned in the center of the tip even if the tip is in nearfield with respect to the inspected tissue.

In any of the embodiments, processor 170 may be configured to processinto images radiation delivered from the imaging region through cores115 to detector 91 and possibly to implement super-resolution algorithmson the detected radiation.

In certain embodiments, inspected tissue 70 may be illuminated by atunable laser (e.g., as laser source 64) as illumination source 160. Aset of spatial images of tissue 70 may be captured, each imagecorresponding to a different wavelength. The resulting is hyperspectralimage may be used for identification of specific types of tissues (e.g.,cancerous tissue) to enhance the imaging. Thus fiber endoscope 105 mayprovide diagnostic possibilities carried out using different wavelengths(in a specified diagnostic wavelength range, such as infraredwavelengths used to measure hemoglobin oxygenation) that are used forspecific purposes and not necessarily for the imaging illumination. Forexample, multiple narrowband wavelengths 62 may be used to providediagnostics with one or more wavelength combinations 174 by processor170. Such combinations may be achieved by using sources with fixedspectral ranges and/or tunable source(s) to change temporally thespectral composition of illumination 85. Examples for diagnostics whichmay be achieved by wavelength combinations 174 include biopsy(diagnostics of removed tissue) and characterization of biologicaltissues in situ e.g., by measuring reflectance at different and veryspecific wavelengths. A non-limiting example includes pulse oximetrywhich may be extracted by measuring a ratio of absorption at wavelengthsof 600-750 nm (e.g., at 660 nm) and 850-1000 nm (e.g., at 910 nm), e.g.,as two distinct wavelength (ranges) 62, utilizing the different spectralabsorption curves of HbO₂ and Hb.

The selection of wavelengths and wavelength bands may be changed duringthe procedure, manually or automatically, to adapt to different stagesin the procedure and different imaging requirements with respect e.g.,to spatial or temporal parameters, encountered site and tissue, etc. Inone example, single wavelength bands may be illuminated and analyzedseparately, to enhance the derived information. Given wavelength bandsmay be used to illuminate the target from different directions to yieldmore detailed spatial information.

In certain embodiments, working channel 112 of endoscope 105 configuredas an ureteroscope may be used to suck out large kidney stones andattach the stones by suction to tip 101 of the endoscope. Treatmentlaser (possibly incorporated in fiber 100, see FIGS. 3A-3C) may then beused to break the stones while the sucking stabilizes the stones andprevents them from moving around during the medical treatment. Suctionmay be applied through working channel 112, and the imaging may be usedto provide feedback regarding the efficiency of the suction and thetreatment. For example, intensive treatment may tend to overcome thesuction and release the attached stone. The imaging may be used todetect the development of stone disengagement from fiber tip 101 and toadjust suction and/or applied energy respectively. In this context,splitting of energy application into several fibers as described abovemay provide more uniform treatment of the stone that employs lowerenergy concentration at any one point of the stone. Energy applicationintensity may be regulated at each of the energy sources to avoid stonedisengagement from the suction.

In certain embodiments, working channel 112 of the ureteroscope may beused to inject liquid and to slightly change the optical conditions offiber 100 such that effectively the focal length of lens 140 at tip 101is changed and focal scanning can be realized to produce the sharpestpossible image per each pixel in the image.

Endoscope 105 may be configured as any type of endoscope and be used tohandle any type of bodily stones or other obstructions, for example, bylaser treatment source 66.

FIGS. 5A-5C are high level schematic illustrations of optical elements140, according to some embodiments of the invention. In certainembodiments, a polarizing optical element 150 (e.g., a Glan Thompsonprism) may be implemented at the end of fiber 100 (FIG. 5A) in additionto imaging lens(es) 140 at tip 101 of the micro-endoscope (e.g., a GRINlens, aspheric lenses). Polarizing optical element 150 may be configuredto increase FOV by polarization multiplexing beyond the limitations ofoptical element(s) 140. Different fields of view 130A, 130B may bepolarization-encoded, folded into endoscope fiber 100 and separated atthe output (e.g., using a polarized beam splitter (PBS) 93 beforereaching detectors 91, 92). Polarization-encoding may be carried outusing different linear polarization directions (e.g. with 45°therebetween), circular polarization etc. Polarization multiplexing maybe used to increase the imaged area either laterally or centrally (seeabove), depending on the configurations of fiber 100 and the optics.Polarization multiplexing may be combined with temporal scanning of thefield of view. Polarization multiplexing may be used to enhance threedimensional depth imaging in place or in addition to enlarging the fieldof view. Different processing algorithms may be applied to the signalsof detectors 91, 92 to provide additional information at regions fromwhich both polarization types are detected. Illumination source 160 forpolarization multiplexing may be non-polarized (with separation topolarization component being carried out optically), or polarized andhave both components.

FIGS. 5B and 5C schematically illustrate embodiments for opticalelements 140, 150 at fiber tip 101, namely an angle deflecting element150 (e.g., a prism) and an imaging optical element 140 (FIG. 5B) and acombined configuration with a faceted GRIN lens 140 (FIG. 5C).

In certain embodiments, certain parts of FOV may be imaged by differentoptical elements 140 (and respective cores 115) to enable opticaltriangulation, e.g., distance measurement from tip 101 and the tissueregion. Such embodiments allow to trade-off FOV with depth informationand thus dynamically allocate imaging resources (e.g., FOV—Field ofView, DOF—Depth of Field) according to situation dependent needs. Incertain embodiments, different polarizations may be used by differentoptical elements 140 imaging the same region, so that using polarizationenhances depth information instead or in addition to extending the FOV(as explained above). Dynamic variation of polarization may be used tomodify the optical performance of fiber 100 during operation. In certainembodiments, different wavelengths may be used by different opticalelements 140 imaging the same region, so that using wavelengthmultiplexing (e.g., using a tunable laser as explained above) enhancesdepth information instead or in addition to extending the FOV (asexplained above).

Dynamic variation of color allocation may be used to modify the opticalperformance of fiber 100 during operation. For example, multiple lasersources having different wavelengths (e.g., with multiple narrowbandwavelengths 62) may be used as illumination source 160, e.g., fourchannels, three of which used to yield color imaging and the forth usedto derive image depth information via triangulation computation. Incertain embodiments, the wavelength used for the fourth channel may beidentical to the wavelength used in one of the other three channels tofacilitate or simplify the triangulation computation.

In certain embodiments, endoscope 105 may be configured to use at leastone non-imaged wavelength range, selected to provide additional depth offield or field of view information. In certain embodiments,polarization, wavelength or spatial multiplexing may be used to image atissue region from different directions, to enable stereoscopic visionof the tissue region. Processor 170 may be configured to derive andprovide stereo-imaging.

Moreover, illumination 85 may be improved in quality in differentrespects, such as its white light spectrum 177 and beam profile 184, asdisclosed above.

In certain embodiments, endoscope 105 may be configured to provide twoor more levels of resolution, allow balancing field of view informationand depth of field information, or allow balance between any other imageparameters by adapting the illumination and/or the image processingprocedure disclosed herein.

FIGS. 6A and 6B are high level schematic illustration of fiber crosssections with different configurations of the cores, according to someembodiments of the invention. FIG. 6C illustrates comparativeexperimental results of full core and hollow core fibers, according tosome embodiments of the invention.

The configuration of the cores (dimension, material, interspaces) may bedesigned to reduce crosstalk between cores 115 and to be less affectedby its banding. For example, crosstalk reduction may be achieved in thefabrication process by generating physical barriers between the cores orby using anti-crosstalk layer(s). Core spacing may be selected to reducecrosstalk between adjacent cores 115 below a specified threshold. Forexample, crosstalk may be reduced by spacing the cores (e.g., by atleast 4μ between cores) and by increasing the refraction indexdifference between the cores and the cladding. The cores may beinterspaced by structures such as air holes or doped polymer material(e.g., with incorporated nanoparticles). Cores 115 may be hollow, madeof polymer material and/or include nanoparticles to control therefractive index. In certain embodiments, contrast may be enhanced byplacing the hardware with the external holes array. In certainembodiments, an optical element (e.g., optical element 94) may be addedbetween the output of fiber 100 and the imaging system and configured toblock the output coming from cladding 113 thus transferring only theinformation going out from optical cores 115. The optical element maycomprise an intensity mask having a value of one for all core locationsand a value of zero for all cladding locations to make all and onlyinformation from the cores to propagate to detector 91.

In certain embodiments, the difference in the refraction index betweencores 115 and cladding 113 may be designed to be large enough, and/orintermediate elements 111 may be introduced to reduce interactionbetween radiation propagating in different cores 115. Core 115 and/orcladding 113 and/or elements 111 may comprise polymer with incorporatednanoparticles. Due to plasmonic resonance of the nanoparticles atspecific wavelengths an effective increased refraction index may beobtained for the doped material. The specific wavelengths may beselected to be close to wavelength bands (e.g., within a few nm, e.g.,±5 nm at most) of illumination source 160 (e.g., three or four colorlasers 62 and/or 64). It is noted that as both the plasmonic resonanceand the bandwidth of illumination lasers are narrow, they may be matchedto yield an effectively increased refractive index by the nanoparticlesat the illumination wavelengths.

In certain embodiments, hollow cores through which no light coupling isobtained may be interlaced as intermediate elements 111 between cores115 (see FIG. 6A). Hollow cores 111 may be used to reduce the effectiverefraction index difference between light conducting solid cores 115 andtheir surrounding medium 113.

In certain embodiments, cores 115 may be hollow (FIG. 6B) and beisolated by doped or non-doped solid polymer. Hollow cores 115 (airholes) were shown to very significantly reduce material losses (FIG. 6C)and are thus exceptionally advantageous when using polymer fibers 100which are characterized by relatively large losses compared to glassfibers. The main advantage of polymer fibers is their flexibility,enable strong bending which is required under certain endoscopeapplications (e.g., treating kidney stones as presented above).

Fiber materials (for cladding 113 and intermediate elements 111 if any)and doping may be selected according to the required refractive indicesand mechanical properties of fiber 100, and may comprise various typesof biocompatible (or not biocompatible, e.g., in non-medical uses)polymers, possibly doped with nanoparticles to influence the refractiveindices. Either or both illumination wavelength ranges and types ofnanoparticles may be selected to optimize the changes in the refractiveindices to optimize the radiation transfer through the cores. In any ofthe embodiments, core diameter D₁, diameter of intermediate elements D₂and distance between cores L may be configured to achieve specifiedoptical performance parameters.

FIG. 7 is a high level schematic flowchart illustrating a method 200,according to some embodiments of the invention. Data processing stagesand control stages may be implemented by respective processors andalgorithms may be implemented by respective computer program product(s)comprising a computer usable medium having computer usable program codetangibly embodied thereon, the computer usable program code configuredto carry out at least part of the respective stages.

Method 200 comprises configuring an endoscope from a fiber with at leastseveral hundred cores (stage 210), e.g., having a multi-core imagingregion or a multi-core tip configured to deliver reflected illuminationalong the fiber for an external detector. Method 200 may compriseimplementing near-field imaging (target imaging at the fiber tip) (stage212) and/or implementing far-field imaging (Fourier plane at the fibertip) (stage 214).

In certain embodiments, method 200 may comprise configuring an endoscopefrom a plurality of fibers, grouped together, each having at least onehundred cores distributed at a fill factor smaller than ¼, or even below1/9, and at least one photonic illumination fiber, implementing threedimensional sensing by handling the cores group-wise with respect toradiation delivered therethrough, implementing super-resolved imaging bymicro scanning over a pitch distance between the cores, and configuringat least one optical element at a distal tip of the fibers to enhance afield of view and/or a depth of field of the endoscope beyond a regionfacing a tip of the fibers and congruent thereto.

Method 200 may comprise at least one of the following stages forreducing losses and/or cross talk between cores: incorporating in thecladding, nanoparticles with plasmonic resonances that are in proximityto illumination (and imaging) wavelengths (stage 220); interspacingcores by intermediate elements (possibly incorporating nanoparticles)having a different refractive index than the cores (stage 230), e.g., by0.1; interspacing cores by air holes (stage 235) and configuring coresas air holes (stage 240), and may comprise reducing crosstalk betweenadjacent cores by interspacing them (stage 245).

In certain embodiments, method 200 may further comprise incorporatingone or more void(s) in the fiber as working channel(s) for treatment,suction and/or illumination (stage 250).

In certain embodiments, method 200 may further comprise splittingtreatment and/or illumination into several fibers operating collectively(stage 260) and/or incorporating additional fibers at the periphery ofthe fiber or of the void(s) (stage 265). Method 200 may comprise coolingincorporated fibers through the working channel (stage 267). In certainembodiments, method 200 may further comprise controlling treatmentand/or suction optically or automatically using optical input during thetreatment (stage 270), and treating bodily stones by the endoscope,e.g., kidney stones with an ureteroscope configuration (stage 275).

Method 200 may further comprise using lens-less configurations, withoutany distal optical elements (stage 277) and/or using distal opticalelements to control the field of view, the depth of field, implementimage multiplexing and/or determine imaging parameters (stage 282), forexample by attaching or producing optical element(s) at the fiber tip(stage 280). Method 200 may comprise enhancing the field of view and/orthe depth of field of the endoscope beyond a region facing the tip ofthe fibers and congruent thereto (stage 285). Method 200 may compriseconfiguring the optical element(s) to image void-facing areas (stage290), for example, using a lens with blocked aperture (stage 292); usingmultiple prisms which optically communicate with the cores (stage 295)and configuring the prisms to image void-facing areas (stage 300), e.g.,associating each prism with one or more cores (stage 305); imagingvoid-facing areas using different polarization, wavelength, wavelengthrange and/or timing of the illumination (stage 310), in the former usingbirefringent optical elements for polarization multiplexing (stage 315).

In certain embodiments, method 200 may further comprise implementingsuper-resolution algorithms (on the detected radiation) to enhanceresolution, field of view and/or depth of field (stage 320).

In certain embodiments, method 200 may further comprise reducing specklepatterns by using Barker codes for optimizing coherence modulation(stage 317). Method 200 may further comprise deriving 3D data usingstructured light illumination and processing (stage 319) and possiblyenhancing super resolution processing using the patterned illumination(stage 322) as done, e.g., in time multiplexing super resolvingconcepts. Method 200 may further comprise beam-shaping the illuminationat the distal tip (stage 324).

In certain embodiments, method 200 may further comprise any of:distributing the cores irregularly (with respect to detector pixelorder) over the tip cross section (stage 332), distributing the cores ata small fill factor (stage 334), and implementing micro-scanning of theregion facing the tip (stage 336). In certain embodiments, method 200may comprise enhancing images by optimizing pixel focus over differenttip positions (stage 338), for example by selecting the best focus foreach pixel from a plurality of images captured at different tippositions, and composing an enhanced imaged from the pixels at theirselected best focus.

In certain embodiments, method 200 may comprise handling the coresgroupwise, possibly with dynamic allocation of cores to groups, toimplement wavefront sensing by each group (stage 340). Method 200 maycomprise implementing light field sensing. e.g., comparing lightdirections at different cores operating in near field and multi-mode.

In certain embodiments, method 200 may further comprise using non-imagedwavelengths to provide additional field of view and/or depth of fieldinformation (stage 350). Method 200 may comprise collecting diagnosticdata using, possibly non-imaged, diagnostic wavelength ranges (stage360). In any of the embodiments, method 200 may comprise configuring theendoscope as a laparoscope or an ureteroscope (stage 370).

In certain embodiments, method 200 may further comprise configuring theillumination to have multiple narrowband wavelengths (stage 362) andpossibly deriving diagnostic data from measurements at differentwavelengths (stage 364) and/or enhancing super resolution processingusing wavelength multiplexing with respect to the multiple narrowbandsources (stage 366). In certain embodiments, method 200 may furthercomprise providing wideband white illumination using a PCF with zerodispersion point(s) selected to yield spectral broadening (stage 368).

Method 200 may further comprise producing the fiber from standardizedfiber modules (stage 380). In certain embodiments, method 200 comprisespackaging the fiber modules into desired fiber cross section forms orconfigurations (stage 382). Method 200 may comprise modifying thespatial relations of the fiber modules along the fiber (stage 385),e.g., to have a circumferential arrangement of fiber modules at thedistal tip and a compact arrangement of fiber modules at the proximaltip of the fiber.

In certain embodiments, method 200 may further comprise applyingconductive coatings to some fiber modules, with other fiber modules asinsulators (stage 387), e.g., for delivering electromagnetic energy tothe fiber tip via the conductive coating, e.g., for heating the fibertip (stage 390), elements associated with the fiber tip and/or asurroundings of the fiber tip. Method 200 may further comprisepreventing fog upon and defogging the at least one optical element whenrequired via a heated conductive coating thereof.

FIGS. 8A-8E are high level schematic illustrations of experimentalimaging results for bundled fibers, according to some embodiments of theinvention. The imaging configuration is illustrated schematically inFIG. 1B. The presented results represent raw data, prior to theapplication of the image processing algorithms described above. FIGS.8A-8C illustrate the imaging of three different targets using a two bytwo bundled fiber (as evident in the four sub-images, each received fromone fiber module, having a side of 450μ and ca. 23,000 cores per fibermodule). The targets are respectively a resolution target, characters(person and doll) and an anatomy model. FIG. 8D illustrates imaging by asingle multicore fiber, 1.8 mm in diameter having ca. 500,000 cores.Both configurations achieve very high resolution which is unattainableby current fibers. FIG. 8E illustrates a result achieved by applyingimage enhancement algorithms applied on the captured image.

FIGS. 9A-9D are images that provide examples for performance ofendoscope 105, according to some embodiments of the invention. FIG. 9Aillustrates an example for the multicore configuration of fiber 100, inthe illustrated non-limiting case, fiber 100 has an external diameter of0.45 mm and includes more than 80,000 cores as well as an integratedillumination channel. The bottom image is a magnified view of the markedsection in the top image. FIG. 9B illustrates image examples byendoscope 105 of a fingernail (a), a mouth (b), teeth (c) and afingertip (d). These images were taken using fiber 100 with externaldiameter of 0.45 mm that includes more than 80,000 cores, and wereprocessed as disclosed above. FIGS. 9C and 9D illustrate examples forprocessing steps, namely the removal of artifacts and core traces (shownin FIG. 9C) and the improvement of resolution and magnification(examples for the quality improvement of the results is shown in FIG.9D). For example, disclosed image processing algorithms provide thecleaned image of FIG. 9D at a resolution of 300,000 pixels.Advantageously, the images obtained from multicore fibers 100 are steadyand are not influences by fiber bending, outperforming prior artmultimode fibers. Advantageously, very thin endoscope 105 provides highresolution medical imaging combined with high maneuverability andcompliance with many medical situations.

In the above description, an embodiment is an example or implementationof the invention. The various appearances of “one embodiment”, “anembodiment”, “certain embodiments” or “some embodiments” do notnecessarily all refer to the same embodiments.

Although various features of the invention may be described in thecontext of a single embodiment, the features may also be providedseparately or in any suitable combination. Conversely, although theinvention may be described herein in the context of separate embodimentsfor clarity, the invention may also be implemented in a singleembodiment.

Certain embodiments of the invention may include features from differentembodiments disclosed above, and certain embodiments may incorporateelements from other embodiments disclosed above. The disclosure ofelements of the invention in the context of a specific embodiment is notto be taken as limiting their used in the specific embodiment alone.

Furthermore, it is to be understood that the invention can be carriedout or practiced in various ways and that the invention can beimplemented in certain embodiments other than the ones outlined in thedescription above.

The invention is not limited to those diagrams or to the correspondingdescriptions. For example, flow need not move through each illustratedbox or state, or in exactly the same order as illustrated and described.

Meanings of technical and scientific terms used herein are to becommonly understood as by one of ordinary skill in the art to which theinvention belongs, unless otherwise defined.

While the invention has been described with respect to a limited numberof embodiments, these should not be construed as limitations on thescope of the invention, but rather as exemplifications of some of thepreferred embodiments. Other possible variations, modifications, andapplications are also within the scope of the invention. Accordingly,the scope of the invention should not be limited by what has beendescribed, but by the appended claims and their legal equivalents.

1. An endoscope having a distal tip and a proximal tip, the endoscopecomprising: at least one multicore fiber module comprising at least onehundred cores distributed at a fill factor smaller than ¼, anillumination source configured to deliver illumination used for imagingby the at least one multicore fiber module, at least one opticalelement, in optical communication with the cores, at the distal tip, adetector, in optical communication with the cores, at the proximal tip,and a processor configured to receive images from the detector; whereinthe endoscope is configured to implement super-resolved imaging by microscanning over a pitch distance between the cores, and wherein theendoscope is configured to implement three dimensional sensing byhandling the cores group-wise with respect to radiation deliveredtherethrough, and to at least one of: enhance, by configuring the atleast one optical element, a field of view of the endoscope beyond aregion facing the cores at the distal tip, and enhance, by configuringthe at least one optical element, a depth of field of the endoscopebeyond a region congruent to the distal tip.
 2. The endoscope of claim1, wherein the illumination source is configured to apply coherencemodulation of the illumination which is based on Barker codes, to reducespeckle patterns.
 3. The endoscope of claim 1, wherein the illuminationsource is configured to have multiple narrowband wavelengths.
 4. Theendoscope of claim 3, wherein the processor is configured to derivediagnostic data from measurements at different wavelengths of theillumination.
 5. The endoscope of claim 3, wherein the processor isconfigured to enhance the implemented super-resolved imaging usingwavelength multiplexing with respect to the multiple narrowbandwavelengths.
 6. The endoscope of claim 1, wherein the illuminationsource is configured to provide wideband white illumination using a PCF(photonic crystal fiber) with at least one zero dispersion pointselected to yield spectral broadening of at least one narrowband source.7. The endoscope of claim 1, wherein the illumination source isconfigured to provide structured light illumination and the processor isconfigured to derive 3D (three dimensional) data from detected patterns.8. The endo scope of claim 7, wherein the processor is furtherconfigured to enhance the implemented super-resolved imaging using thestructured light illumination by applying a time multiplexing superresolution approach.
 9. The endoscope of claim 1, wherein the at leastone optical element is further configured to beam-shaping the deliveredillumination.
 10. The endoscope of claim 1, wherein the at least oneoptical element is coated by a conductive coating connected to anelectric circuit configured to heat the at least one optical element viathe conductive coating to prevent fog upon and to defog the at least oneoptical element when required.
 11. The endoscope of claim 1, furthercomprising a laser treatment source configured to treat tissue imaged bythe endoscope.
 12. A method comprising: configuring an endoscope from atleast one multicore fiber module comprising at least one hundred coresdistributed at a fill factor smaller than ¼, implementing super-resolvedimaging by micro scanning over a pitch distance between the cores,implementing three dimensional sensing by handling the cores group-wisewith respect to radiation delivered therethrough, and configuring atleast one optical element at a distal tip of the endo scope to enhanceat least one of a field of view and a depth of field of the endoscopebeyond a region facing a tip of the fibers and congruent thereto. 13.The method of claim 12, further comprising reducing speckle patterns byusing Barker codes for optimizing coherence modulation of anillumination used for imaging by the at least one multicore fibermodule.
 14. The method of claim 12, further comprising configuring anillumination used for imaging by the at least one multicore fiber moduleto have multiple narrowband wavelengths.
 15. The method of claim 14,further comprising deriving diagnostic data from measurements atdifferent wavelengths of the illumination.
 16. The method of claim 14,further comprising enhancing the implementing super-resolved imagingusing wavelength multiplexing with respect to the multiple narrowbandwavelengths.
 17. The method of claim 12, further comprising providingwideband white illumination to the at least one multicore fiber moduleusing a PCF with at least one zero dispersion point selected to yieldspectral broadening of at least one narrowband source.
 18. The method ofclaim 12, further comprising deriving 3D data using structured lightillumination used for imaging by the at least one multicore fiber moduleand corresponding processing.
 19. The method of claim 18, furthercomprising enhancing the implementing super-resolved imaging using thestructured light illumination.
 20. The method of claim 12, furthercomprising beam-shaping an illumination used for imaging by the at leastone multicore fiber module at the distal tip.
 21. The method of claim12, further comprising preventing fog upon and defogging the at leastone optical element when required via a heated conductive coatingthereof.
 22. The method of claim 12, further comprising laser treating,by the endoscope, tissue imaged by the at least one multicore fibermodule.